Even within Poland some details are different in different regions.
The quote in the first post says:
decorated with sprigs of boxwood (bukszpan),
In my area it is never boxwood, but cowberry (borówka). Another symbol known in the whole country are willow catkins (bazie, kotki).
What are the most important items in the basket?
- eggs, often painted
- salt and pepper
- bread
- a lamb made of sugar, although locally ones made of bread are also popular (believing Polish Wikipedia, they were made of bread in the past)
- everything that is going to be eaten on the Easter breakfast - ham, cheese, sausage, cakes
- also some more commercial Easter symbols, like chocolate hare or chicks
- cowberry leaves, willow catkins
- other decorations
What is also important to mention - I don't know how it looks like in another countries, but I think it might be also a typical Polish tradition - our Easter palms have almost nothing in common with palm tree leaves, with which Jesus entering Jerusalem was greeted.
See: pl.wikipedia.org/wiki/Palma_wielkanocna
In some areas contests are organized for the longest and the most beautiful palm:
dzienniklodzki.pl/artykul/3803869,niedziela-palmowa-w-lowiczu-diecezjalny-konkurs-biskupa-lowickiego-zdjecia,id,t.html
